Hi @joverbey,
There’s some clarification needed here.
First of it seems you’re not actually talking about category pages but rather regular pages in wordpress (you’re querying page post_type).
Second, why are you not simply putting these images in the respective child page? Maybe even as featured image since that seems to be what you want it to be used as.
Some other notes that may be good to know:
* Don’t use query_posts. You’ll only be messing with the main query in a bad way. Instead create a new query with wp_query. https://codex.wordpress.org/Class_Reference/WP_Query
* Try to avoid inline styling of elements. Put this in your style.css instead
img{ max-width: 100%; height: auto; }
